Improvement in slide-valves



UNITED STATES PATENT OEEICEo JAMES LARKIN, OF DETROIT, MICHIGAN.

IM PROVEM ENT IN SLI DE-VALVES.

Specification forming part of Letters Patent N0. 102,410, dated April 26, 1870.

To all whom fit may concern:

Be it known that I, JAMES LARKIN, of Detroit, in the county of 'Vayne and State of Michigan, have invented new and usei'ul Improvements on the Steam-En gine.

The nature of my invention consists in the construction of'a steam slide-valve,valvecover, and steam-chest cover so that the pressure of steam can be kept from the slide-valve as may be desired; and I do hereby declare that the following is al'ull and exact description of the construction and operation of the same, reference being had to the annexed drawing, making a part of this specification, in which- Figure lis a side elevation of the steamchest.

I construct my steam slide-valve (as shown on the drawing, lettered A A) of any suitable dimensions, with two extra or back faces, as shown at B B, enough smaller, according to discretion, than the steam-faces A A to allow steam-pressure enough on them to balance the pressure of the atmosphere and of the steam which escapes under them from the cylinder.

I construct what I term a valvecover (as shown on the drawing, lettered G) with aplaned face to rest steam-tight on the back faces, B B, and to t between two chipping-pieces, as shown at S S, so that the sliding oi' the valve cannot cramp it, with two top parts to it, as shown at It It, and about the size oi' the faces B B, having chambers in them for the spiral springs, as shown at D D, for the purpose of getting a spring-pressure on the valve and valve-cover.

I construct my steam-chest cover, as shown at G, with two smiling-boxes (shown at H IL) in or on it suitable for the parts of the valveeover C (shown atItB) for the purpose oi'having stuling packed around them to prevent the steam from getting into the stuflingboxes, and by that means the pressure of the steam is kept from the valve equal to the'supercial area of the parts B R of the valve-cover,which passes through the stuffing-boxes.

I construct two cover-glands, I I, as shown, with parts J J, suitable to tit into the stuflin gboxes H H, and likewise to fit overthe parts It R of the valve-cover C, in order to press the stuing all around them. I screw my steamchest cover ou by any suitable means, like other steam-chest covers. I screw my coverglands into the described stuffing, and over the parts R R of the valve-cover, by means of four stud-bolts, (shown at u,) which I fasten into the steam-chest cover. I put two flat pieces, E E, into the top ot' the chambers over the spiral springs in the parts It R of the valvecover, and press them down, as may be necessary, by means of two set-screws, F F, which I screw into the cover-glands.- I have holes N N through my valve, between the faces A A and B B, for the valve-stem K to pass through, and, passing through the gland L and the stu'iing-box M, as shown, I connect the valve-stem to the valve A A by means of four nuts, O 0 and P P, as shown, which I screw on the end of it on both sides of a piece, Q, shownfon the back of the valve, for the purpose of ladjustin g the valve and working it, leaving it ready for connection and operation.

I consider one View and description oi' this invention sufficien t, as variations in constructing the proportions or shapes are optional, but the principle must remain the same.

I wish to note that I can use the described valve singly, as shown, or for cutting off the steam at any part ofthe stroke; that I can use it over another valve and still be the same.

I wish to mention that I intend to round oit and fillet the sharp corners ot' the parts B of the valve-cover, the stuffing-boxes H, and the parts J ofthe cover-glands when constructing them, for the reason that they mold better, and I consider it easier to pack the stuffing steamtight around them when the sharp corners are thus filleted and taken off.

I intend also to have a screw-plug or oil-cup in the cover-glands, in order to oil them and to let out any water which may accumulate from condensed steam.

What I claim as my invention, and desire to secure by Letters Patent, is p A double-seated valve, A B, and balanceplate O, provided with two boxes, B, springs D, caps E, and set-screws F, in combination with a steam-chest cover G, provided With openings H, and glands I J, when constructed and arranged in the manner substantially as herein described and set forth.

JAMES LARKIN.

Witnesses:

DENIS OBEIEN, CHARLES FOLEY. 

